As males and females suffering from hereditary or environmental alopecia increase in the modern society that values beauty, various studies have been conducted actively all over the world to develop a method for treating alopecia and stimulating hair growth.
Human hairs exist in a number of about 100-150 thousands and each hair repeats growth and atrophy through a different cycle. Hairs repeat a three-step cycle including the anagen in which hair growth occurs, the catagen in which hairs, after the completion of the anagen, undergo slow-down in metabolic process while maintaining its shape, and the telogen in which hair papillae shrink and follicles gradually shrink, resulting in push-up of hair roots and reduction of follicles. Such a cycle and life of hairs may be varied with various conditions, including nourishment, medical history, heredity, constitution, hormone secretion and aging. In the case of a human, the whole hairs are not present at the same follicle cycle and several thousands of hairs exist in each of the three phases.
Meanwhile, most hairs are present in the anagen. Particularly, in the case of a healthy young adult, hairs are present in the anagen and telogen at a ratio of about 9:1. In the case of a patient suffering from alopecia, the ratio decreases to about 2:1.
Male pattern alopecia, the most common type of alopecia, is caused by activation of hereditary sensitivity to circulating androgen hormone. This may occur both in males (50%) and females (30%), and mainly in the white race. As aging proceeds, in a part of alopecia cases, the width and length between one hair and another hair are gradually changed prematurely, and thus terminals hairs are gradually converted into short and sparse colorless soft hairs. In the case of a man, most alopecia occurs at the crown of the head. In the case of a woman, hairs become sparse in the whole part of scalp.
Among the existing anti-alopecia treating agents, minoxidil, an external application agent the use of which is approved by FDA in USA based on its effect, is known to be effective for inducing hairs in the telogen to hairs in the anagen and maintaining the induced anagen cycle of hairs continuously, in addition to a vasodilatation function as a potassium channel opener. However, many people regard hair growth caused by minoxidil as insufficient in cosmetic effects. Therefore, three is a need for developing a material inducing hair growth at a higher rate while satisfying a cosmetic effect sufficiently.